Sample size in consumer test and descriptive analysis

This article deals with sample size (n) estimation by computer simulation using the variance of consumer and in-house sensory tests. The current sample size used in descriptive analysis was also examined. The sample size ranging from 20 to 200 was used to detect a difference ranging from 0.0 to 1.0 on a 9-point hedonic scale. For the simulated consumer data, significant difference was first observed at a difference of 0.60 when n = 40. Increasing the difference to above 0.60, the first significance likewise appeared when n = 40. Based on the variability used in the study, these results support the commonly cited sample size of 40-100. Thus, the role of the difference to be detected is very important in determining the sample size (base size). The variance can be obtained from historical data. In this study, the difference ranging from 0.60 to 1.00 is critical and can be used by the research and sensory analysts as a guide. Therefore, the analysts must have an idea of the size of hedonic differences among formula or products to be compared in determining the appropriate sample size. The power of the test for various sample sizes is provided through plots of power versus n. For descriptive analysis, the results showed that the recommended minimum is n = 5, noting that in most cases, judges differed by 1 unit on a 15-point rating scale. The power of the test is also reported for n ranging from 5 to 14 judges.